After trying a lot of solutions to realize a very low cost X Y
scanner for a laser pointer, I choose the "loudspeaker"
way :Build
a 10$ X Y Laser scanner !

Here is the very last version more simple, cheaper
and more efficient that the 10$ one (but for low angle deviation)

Mechanical construction :

You must buy 4 very little loudspeakers (here, in France, we
can buy D = 30 mm 8 ohms loudspeaker for 0.25 $ each one !). You
then attach the 4 loudspeakers on an aluminum plate (4 x 90°)
with screws.You make a d=10 mm hole in the plate in front of each
loudspeaker axis. You then electrically connect a loudspeaker to
the opposite one + to - and - to + terminals : If you put a DC
current, one loudspeaker is pushing, the other one is pulling. On
each loudspeaker, you glue (Araldite, epoxy..) on the mobile
part, in the center and through the plate hole a little piece of
PCB with a "L" shape. The short "L" lenght
end is glued to the loudspeaker. The long "L" lenght
end is in direction of the opposite loudspeaker. Once achieved,
you get 4 epoxy pieces which are like 4 x 90° rays on the same
wheel. L lenght has been chosen in such a way there is about 10
mm between one "L" end and the opposite loudspeaker
corresponding other "L" end. You then glue (with
silicon or rubber glue) a little 8 x 8 mm mirror : each mirror
corner is glued to each epoxy "L". A very good place to
get litlle good mirror : an old laser printer (in the laser drum
mechanism itself)

Or you can use a very more simple solution:
simply connect directly (with a 3.5 mm Jack male connector) to
your PC Sound card output: Left for X and Right for Y :

You have the 2 high resolution X & Y D/A
converters, amplitude (volume) is very easy to set and you have a
.WAV... standardised file format and many tools to create, edit
and transform your XY movies.

One problem with sound card: there is no way to
put laser on and off. Another problem: DC is removed the center
of the display depends of the figure displayed it self.

Due to the fact that, for X Y laser animation,
there are never X or Y pulses (from mini to maxi for example) we
are thinking to a very simple solution added to the 2 audio power
amplifiers: if a very fast pulse occurs on X (from mini to maxi)
we put laser ON. if a very fast pulse occurs on Y (from mini to
maxi) we put laser OFF. We think that, if pulses has the minimum
width, it will be unvisible and the coresponding electronic parts
will be minimum...

When you realize fixed or animated
files for XY laser, important thing is the perimeter of the
figure, longer it is and harder for the laser to follow it. Or
you must slow it and you have blinking problem. You always must
wait for a while for each point of the figure. For example if you
want to go from (x,y) = (0,0) to (10,10)

A very good trick to check your
file : just hear the loudspeakers noise : a well made file
generate a very little "buzz" noise with only low
frequency sound. If your XY file sounds noisy with treeble
components, it has been probably bad made and can be improved...

Another simple useful trick : if
you have an oscilloscope, connect input A to X audio amplifier
output and input B to Y audio amplifier output and set the scope
to "XY mode" : you must see exactly your display on the
scope! in case of problem connect the scope directly on the DAC
output. (perhaps you need a capacitor to smooth). With a scope,
you can understand that DAC and amplifiers must also be well made
to get a good result : not only loudspeakers scanner !